® | Official Canadian Boating License

Emergency: Propeller Strikes

Boat engine propellers spin at very high speeds and have a lot of power. They will cause serious harm if you come in contact with one. Always operate your boat with caution to avoid any injuries from propellers; this is a common injury that can easily be avoided.

A typical three blade propeller running at 3,200 rpm can inflict 160 impacts in one second!


To help reduce the risk of a propeller strike:

  • Turn off the engine when retrieving a person from the water;
  • People in the water may not be visible from the helm. Before starting your engine, walk around the boat and look in the water to make certain that no one is in the water near the boat;
  • Account for all your passengers prior to starting the engine;
  • Never allow passengers to board or exit your boat from the water when engines are on – or idling (your propeller may continue to spin);
  • Educate passengers about the location and danger of the propellers;
  • Be especially alert when operating in congested areas and never enter swimming zones;
  • Take extra precautions near boats that are towing skiers or inflatables;
  • Always secure a lanyard (kill line); and
  • Install a propeller cage or guard.


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